1Nephrology, Department of Public Health, University Federico II of Naples, 2Department of Nephrology, Second University of Naples, 3Department of Neurosciences, Unit of Clinical Pharmacology, University Federico II of Naples, Naples, Italy

Purpose: The aim of this study was to determine the prevalence of nonadherence in a cohort of renal transplant recipients (RTRs) and to evaluate prospectively whether more intense clinical surveillance and reduced pill number enhanced adherence.Patients and methods: The study was carried out in 310 stable RTRs in whom adherence, life satisfaction, and transplant care were evaluated by specific questionnaires (time 0). The patients under tacrolimus (TAC; bis in die [BID]) were then shifted to once-daily TAC (D-TAC) to reduce their pill burden (Shift group) and were followed up for 6 months to reevaluate the same parameters. Patients on cyclosporin or still on BID-TAC constituted a time-control group.Results: The prevalence of nonadherence was 23.5% and was associated with previous rejection episodes (P<0.002), and was inversely related to Life Satisfaction Index, anxiety, and low glomerular filtration rate (minimum P<0.03). Nonadherent patients were significantly less satisfied with their medical care and their relationships with the medical staff. A shift from BID-TAC to D-TAC was performed in 121 patients, and the questionnaires were repeated after 3 and 6 months. In the Shift group, a reduction in pill number was observed (P<0.01), associated with improved adherence after 3 and 6 months (+36%, P<0.05 versus basal), with no change in controls. Decreased TAC trough levels after 3 and 6 months (−9%), despite a slight increase in drug dosage (+6.5%), were observed in the Shift group, with no clinical side effects.Conclusion: The reduced pill burden improves patients' compliance to calcineurin-inhibitors, but major efforts in preventing nonadherence are needed.